Production of acetylene and hydrogen in the electric arc



Feb. 24, 1931. I o, sguu'r 1,794,004

PRODUCTION OF ACETYLENE AND HYDROGEN IN THE ELECTRIC ARC Filed Aug. 19. 1929 wwentoz OZFa-Fisenhul' 33 71 1:3 Guam my 1 rated hydrocarbons,

Patented Feb. 24, 1931 UNITED STATES PATENT OFFICE- OTTO EISENHUT, 0F HEIDELBERG, GERMANY, ASSIGNOIB. TO I. G. FAJBBENINDUSTRIE AKTIENGESELLSCHAFT, 0F FRANKFORT-ON-TH'E-MAIN, GERMANY, A CORPORA- 'IION OF GERMANY rnonvcsuon or AcnrYLnnr: AND HYDROGEN IN THE nnnc'rmc ARC Application filed August 19, 1929, Serial No.

This invention relates to improvements in the manufacture and production of acetylene and hydrogen in the electric arc.

It is already known that valuable unsatusuch as acetylene can be roduced from saturated hydrocarbons, as or example methane by treating the gases with an electric arc.

I have now established the fact that the yield of acetylene for a given concentration of saturated hydrocarbons in the gas to be treated is dependent on the length and on the shape of the electric arc. When passing bydrocarbons insa disperse phase, such for example as a gas initially rich in methane, through several electric arcs one after another, the said fact may be exploited in an advantageous manner with the production of high yields by adapting the length and, if desired, also the shape of the electric arcs to the changing composition of the gas in such a manner that in each are a maximum conversion is obtained. The acetylene which is formed may be removed after passage through one or several electric arcs. After leaving the last electric are a residual gas is finally obtained which consists substantially of hydrogen and which contains at most about 1 per cent of saturated hydrocarbons, for example 1 er cent of methane.

This method of working is very valuable because practically the entire quantity of the hydrocarbons employed is converted into val uable unsaturated compounds and moreover a practically pure hydrogen is obtained. This hydrogen may be employed for hydrogenation processes or in part may be subjected again to the process hereinbefore described after the addition, for example of natural a As examples of hydrocarbons in the disperse phase suitable for treatment according to the process of the present invention may be mentioned, gases and vapours consisting of or containing hydrocarbons, such as methane, ethane, natural gases, gases obtained by distillation of coal of all varieties, or similar bituminous materials, cracking gases, oil or tar vapours. Further may be mentioned nebulized or otherwise finely dishale, peat 387,053, and in Germany February 2, 1926.

small amounts although larger amounts thereof may of course also be employed. The employment of hydrogen tends to suppress an undesirable formation of carbon.

The process may be carried out under any pressures under which electric arcs can be obtamed, that is to say at atmospheric pressure or at reduced pressures down to about 1/ 20 of an atmosphere and at an elevated pressure. Different pressures may for example also be employed for different arcs.

As a rule arcs having voltages ranging between 1 and 3 kilovolts are employed, but much higher voltages or lower voltages, as for example of 10 kilovolts or more or of down to about 500 volts or less. The energy of the arc furnaces may be up to 2000 kilowatts oreven more.

The following examples will further illustrate the nature of this invention, but the invention is not restricted to these examples. Example 2 is, with reference to the accompanying drawing.

Example 1 The residual gas consists of hydrogen contain- The ing less than 1 per cent of methane. ratio of the lengths of the arcs is 4: 5: 6.

As a result Ewample 2 The drawing illustrates diagrammatically and in vertical section a plant for the production of acetylene accordlng to the present Invention. P

G is a gas container. 0 O and 0 are are furnaces in which arcs of different length can be produced. A, E and E are pipelines for introducing gas to the said are furnaces. T1, T and T are scrubbers. D D and D111 are branch pipes for the introduction of sol vents to the said scrubbers. B B and B are pipe lines for the introduction of the gases issuing from the arc furnaces to the said scrubbers. E E and E are pipes for the withdrawal of the scrubber gases from the scrubbers. F F and F are branches for the withdrawal of the washing liquid from the scrubber. V is a container for the scrubbing liquid and H a pipe for the withdrawal of scrubbing liquid therefrom. P is a pump for pumping scrubbing liquid to the towers by way of the pipe C.

A preferred method of working with this said apparatus is described in the following. A gas containing hydrocarbons derived from the destructive hydrogenation of coal and having the composition: 63 per cent of hydrogen, 18 per cent of methane, 8 percent of ethane, 4 per cent of propane, 2 per cent of butane and the remainder nitrogen and small amounts of unsaturated hydrocarbons contained in the container G is introduced by way of the pipe line A into the top of an upright electric arc furnace 0 containing an electric arc of 200 millimetres in length. A gas mixture is obtained which contains 8 per cent of acetylene which is passed by way of the pipe B; to the bottom of a scrubber T Cyclohexanone from the container V is introduced with the aid of the pump P and pipe (3 by means of the branch D into the top of the said scrubber T After removal of the acetylene by washing out with cyclohexanone, a gas containing about 72 per cent of hydrogen, 24 per cent of hydrocarbons and 4 per cent of nitrogen issues at the top of the said scrubber. This gas mixture is passed on through the pipe E to a second arc furnace 0 containing an arc of 280 millimetres in length. The gas mixture issuing from the said furnace which contains 8 per cent of acetylene is passed by way of the pipe B into the scrubber T into which cyclohexanone is introduced by way of the pipe D A gas containing 14 per cent of methane and its homologues besides hydrogen and nitrogen issues from the scrubber E This gas mixture may be converted in a third are furnace 0 containing an arc of 350 millimetres in length into a mixture containing 7 per cent of acetylene. This gas mixture is passed on by way of the pipe B to the scrubber T into which cyclohexanone is introduced at D After removing the acetylene drogenation of coal.

duced in the first furnace,

a gas mixture issues at E which consists of 93 per cent of hydrogen, from? to 3 per cent of hydrocarbons and the remainder nitrogen, which may be employed The shape of the said arcs may also be modified to suit the individualconditions by the insertion of suitable insulating means. The ratio of the lengths of directly for the hy-' the arcs according-to the said example is 2.8:4z5. These ratios of wide variation.

I claim i 1. A process for the production of acetylene and hydrogen which comprises passing hydrocarbons in a disperse phase through several arcs one after another and adapting the length of the arcs to the changing composition of the gas in such a manner that in each are a maximum conversion is obtained by increasing the length of each consecutive arc.

2. A process for the production of acetylene and hydrogen, which comprises passing a gas comprising methane through three arcs one after another, the lengths of which have a ratio of about 28:4:5 respectively.

3. An apparatus for the production of acetylene and hydrogen from hydrocarbons in the areof course capable disperse phase, comprising several arc furnaces in series, means for theproduction of arcs therein, each having a length longer than that of the are next before it and scrubbers interposed between any of the from the other end of said scrubber to one end of said second electric arc furnace, means i in said furnace for producing an arc of greater length than that which would be proa second scrubber, a pipe for passing gases from the other end of said second furnace to one end of said second scrubber, a third are furnace, a pipe for passing gases from the other end of said second scrubber to one end of said third electric arc furnace, means in said furnace for producing an arc of greater length than that which would be produced in the second furnace, and a pipe for withdrawinggases from the other end of the said third furnace.

In testimony whereof'I have hereunto set my hand.

OTTO EISEN HUT.

a pipe for passing gases IOU 

